As was half expecting the shutter is royally gummed up.
It can be cocked, but refuses to fire.
It won't fire via cable release because the cable release cannot be depressed! But if I set it on any speed I can cock it, it opens up and closes whenever it feels like doing so.
There is a "B" but no "T" setting. This is my first Synchro Compur so I'm a bit leery of doing anything to cause further mischief.
Other than sending it off to a tech, are there any suggestions?
The only caution I've read is to never open one of these up from the back lest the shutter blades create some calamity.

Any suggestions? Will Ronson lighter fluid harm Synchro Compurs?